Getting this at boot on my PowerMac G4 MDD (Dual CPU) when CONFIG_NETCONSOLE=y is enabled (kernel 6.4.8). Also happens on kernel 6.5-rc5 but not always:

[...]
gem 0002:00:0f.0 eth0: Found BCM5421 PHY
gem 0002:00:0f.0 eth0: Link is up at 1000 Mbps, full-duplex
gem 0002:00:0f.0 eth0: Pause is enabled (rxfifo: 10240 off: 7168 on: 5632)
IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
printk: console [netcon0] enabled
------------[ cut here ]------------
netpoll_send_skb_on_dev(): eth0 enabled interrupts in poll (gem_start_xmit+0x0/0x4f0)
WARNING: CPU: 1 PID: 1 at net/core/netpoll.c:370 netpoll_send_skb+0x2d8/0x33c
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G                T  6.4.8-gentoo-PMacG4 #1
Hardware name: PowerMac3,6 7455 0x80010303 PowerMac
NIP:  c0973b20 LR: c0973b20 CTR: 00000000
REGS: c144bb20 TRAP: 0700   Tainted: G                T   (6.4.8-gentoo-PMacG4)
MSR:  00029032 <EE,ME,IR,DR,RI>  CR: 44482288  XER: 00000000

GPR00: 00000000 c144bbe0 c14d15a0 00000000 00000000 00000000 00000000 00000000 
GPR08: 00000000 00000000 00000000 00000000 00000000 00000000 00000030 00000000 
GPR16: 00000000 00009032 c11547cc c11b0000 00000000 c11bc5cc c238d53c 00001032 
GPR24: 00000000 c1483440 00000041 00001032 c248b700 c238d53c c223c000 c24bd720 
NIP [c0973b20] netpoll_send_skb+0x2d8/0x33c
LR [c0973b20] netpoll_send_skb+0x2d8/0x33c
Call Trace:
[c144bbe0] [c0973b20] netpoll_send_skb+0x2d8/0x33c (unreliable)
[c144bc20] [c082bf44] write_msg+0x154/0x178
[c144bc60] [c00caad8] console_flush_all+0x1f0/0x55c
[c144bd00] [c00caf04] console_unlock+0xc0/0x1e4
[c144bd40] [c00cc8bc] vprintk_emit+0x1b8/0x37c
[c144bd70] [c00cd418] _printk+0x6c/0xa0
[c144bdc0] [c00cb7ec] register_console+0x2ac/0x4b4
[c144be00] [c104be90] init_netconsole+0x328/0x45c
[c144be60] [c00079bc] do_one_initcall+0x64/0x2cc
[c144bed0] [c1004534] kernel_init_freeable+0x2bc/0x3e0
[c144bf10] [c0007e3c] kernel_init+0x28/0x154
[c144bf30] [c001c2ec] ret_from_kernel_user_thread+0x10/0x18
--- interrupt: 0 at 0x0
NIP:  00000000 LR: 00000000 CTR: 00000000
REGS: c144bf40 TRAP: 0000   Tainted: G                T   (6.4.8-gentoo-PMacG4)
MSR:  00000000 <>  CR: 00000000  XER: 00000000

GPR00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
GPR08: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
GPR24: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
NIP [00000000] 0x0
LR [00000000] 0x0
--- interrupt: 0
Code: 3929e85d 89490002 2c0a0000 4082ff6c 815e0078 3c60c0d1 39000001 7fc4f378 38632308 99090002 80aa0064 4b6edbd1 <0fe00000> 92e1001c 7d2000a6 71298000 
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
raw_local_irq_restore() called with IRQs enabled
WARNING: CPU: 1 PID: 1 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x3c/0x60
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G        W       T  6.4.8-gentoo-PMacG4 #1
Hardware name: PowerMac3,6 7455 0x80010303 PowerMac
NIP:  c0b404a4 LR: c0b404a4 CTR: 00000000
REGS: c144bb10 TRAP: 0700   Tainted: G        W       T   (6.4.8-gentoo-PMacG4)
MSR:  00029032 <EE,ME,IR,DR,RI>  CR: 44482282  XER: 20000000

GPR00: 00000000 c144bbd0 c14d15a0 00000000 00000000 00000000 00000000 00000000 
GPR08: 00000000 00000000 00000000 00000000 00000000 00000000 00000030 00000000 
GPR16: 00000000 00009032 c11547cc c11b0000 00000000 c11bc5cc c238d53c 00001032 
GPR24: c11dfecc 00000030 c119fcc8 00001032 c248b700 c238d53c c223c000 00000000 
NIP [c0b404a4] warn_bogus_irq_restore+0x3c/0x60
LR [c0b404a4] warn_bogus_irq_restore+0x3c/0x60
Call Trace:
[c144bbd0] [c0b404a4] warn_bogus_irq_restore+0x3c/0x60 (unreliable)
[c144bbe0] [c09739d4] netpoll_send_skb+0x18c/0x33c
[c144bc20] [c082bf44] write_msg+0x154/0x178
[c144bc60] [c00caad8] console_flush_all+0x1f0/0x55c
[c144bd00] [c00caf04] console_unlock+0xc0/0x1e4
[c144bd40] [c00cc8bc] vprintk_emit+0x1b8/0x37c
[c144bd70] [c00cd418] _printk+0x6c/0xa0
[c144bdc0] [c00cb7ec] register_console+0x2ac/0x4b4
[c144be00] [c104be90] init_netconsole+0x328/0x45c
[c144be60] [c00079bc] do_one_initcall+0x64/0x2cc
[c144bed0] [c1004534] kernel_init_freeable+0x2bc/0x3e0
[c144bf10] [c0007e3c] kernel_init+0x28/0x154
[c144bf30] [c001c2ec] ret_from_kernel_user_thread+0x10/0x18
--- interrupt: 0 at 0x0
NIP:  00000000 LR: 00000000 CTR: 00000000
REGS: c144bf40 TRAP: 0000   Tainted: G        W       T   (6.4.8-gentoo-PMacG4)
MSR:  00000000 <>  CR: 00000000  XER: 00000000

GPR00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
GPR08: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
GPR24: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
NIP [00000000] 0x0
LR [00000000] 0x0
--- interrupt: 0
Code: 38000000 38600000 39400000 4ca20020 9421fff0 3c60c0ca 7c0802a6 39400001 386389e0 9949e728 90010014 4b52124d <0fe00000> 80010014 38210010 7c0803a6 
---[ end trace 0000000000000000 ]---
netconsole: network logging started
[...]

Some data about the machine:
 # lspci 
0000:00:0b.0 Host bridge: Apple Inc. UniNorth 2 AGP
0000:00:10.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV350 [Radeon 9550/9600/X1050 Series]
0001:00:0b.0 Host bridge: Apple Inc. UniNorth 2 PCI
0001:00:12.0 USB controller: NEC Corporation OHCI USB Controller (rev 43)
0001:00:12.1 USB controller: NEC Corporation OHCI USB Controller (rev 43)
0001:00:12.2 USB controller: NEC Corporation uPD72010x USB 2.0 Controller (rev 04)
0001:00:13.0 Mass storage controller: Silicon Image, Inc. SiI 3112 [SATALink/SATARaid] Serial ATA Controller (rev 02)
0001:00:15.0 Serial controller: MosChip Semiconductor Technology Ltd. PCI 9865 Multi-I/O Controller
0001:00:15.1 Serial controller: MosChip Semiconductor Technology Ltd. PCI 9865 Multi-I/O Controller
0001:00:15.2 Parallel controller: Illegal Vendor ID Device 9865
0001:00:16.0 Network controller: Broadcom Inc. and subsidiaries BCM4306 802.11b/g Wireless LAN Controller (rev 02)
0001:00:17.0 Unassigned class [ff00]: Apple Inc. KeyLargo Mac I/O (rev 03)
0001:00:18.0 USB controller: Apple Inc. KeyLargo USB
0001:00:19.0 USB controller: Apple Inc. KeyLargo USB
0001:00:1b.0 USB controller: NEC Corporation OHCI USB Controller (rev 43)
0001:00:1b.1 USB controller: NEC Corporation OHCI USB Controller (rev 43)
0001:00:1b.2 USB controller: NEC Corporation uPD72010x USB 2.0 Controller (rev 04)
0002:00:0b.0 Host bridge: Apple Inc. UniNorth 2 Internal PCI
0002:00:0d.0 Unassigned class [ff00]: Apple Inc. UniNorth 2 ATA/100
0002:00:0e.0 FireWire (IEEE 1394): Apple Inc. UniNorth 2 FireWire (rev 01)
0002:00:0f.0 Ethernet controller: Apple Inc. UniNorth 2 GMAC (Sun GEM)
 
# inxi -bz
System:
  Kernel: 6.4.8-gentoo-PMacG4 arch: ppc bits: 32 Console: pty pts/0
    Distro: Gentoo Base System release 2.13
Machine:
  Type: PPC System: PowerMac3 6 details: N/A mobo: PowerMac3,6 MacRISC3 Power
    Macintosh serial: <filter>
CPU:
  Info: single core 7455 altivec supported [MT MCM] speed (MHz): avg: 1417
Graphics:
  Device-1: AMD RV350 [Radeon 9550/9600/X1050 Series] driver: radeon v: kernel
  Display: x11 server: X.org v: 1.21.1.8 driver: X: loaded: radeon
    unloaded: fbdev,modesetting dri: r300 gpu: radeon
    resolution: <missing: xdpyinfo/xrandr> resolution: 1920x1080
  API: OpenGL v: 3.3 Mesa 23.1.5 renderer: softpipe
Network:
  Device-1: Broadcom BCM4306 802.11b/g Wireless LAN driver: b43-pci-bridge
  Device-2: Apple UniNorth 2 GMAC driver: gem
  Device-3: gmac driver: gem

Kernel .config and full dmesg attached.

Regards,
Erhard F.